But at the grocery store, my choices don’t just stop at plain versus chocolate milk. There’s also fat content to consider and milk labeled organic, RBST-free and lactose-free. And beyond the grocery store, there’s the raw milk versus pasteurized milk debate. With so many choices, how do you know which one you should buy? This guide will help you cut through the confusion.

And don’t be fooled: reduced-fat (2%) milk is not a low-fat food. One cup has 5 grams fat, 3 of them the saturated kind. (Check out these 6 other surprisingly unhealthy foods.) You won’t miss out on milk’s nutritional boons when you opt for low-fat or nonfat milk (sometimes called “skim”): per cup, all varieties deliver about one-third of the recommended daily value for calcium and at least 20 percent of the daily value for riboflavin, phosphorus and vitamin D.

Organic or not? Polls suggest people associate organic milk with superior nutrition, better treatment of animals and a healthier planet. But there’s no evidence that organic milk is more nutritious. While preliminary research has suggested that grass-fed cows produce milk with more vitamin E and heart-healthy omega-3 fats than cows fed grains, organic standards don't require that cows be solely grass-fed. (Farmers must use organic fertilizers and pesticides and may not give cows preventive antibiotics or supplemental growth hormones; animals must have access to the outdoors year-round and at least 120 days per year of grazing.)

rBST-free or not? The claim “rBST-free” indicates milk produced without using the artificial growth hormone recombinant bovine somatotropin, or rBST. Giving this hormone to a cow boosts its milk production by about five quarts per day. Some consumers believe that treating cows with the supplemental hormone is inhumane, but the Food and Drug Administration (FDA) maintains that treating cows with rBST does not harm the animals—or significantly affect the hormone content of milk. In fact, all milks—even from cows not treated with rBST—contain naturally-occurring hormones. Note: All organic milks are rBST-free, but not all rBST-free milks are organic (i.e., farmers may use pesticides, fertilizers, etc.).

Lactose-free? This type of milk is basically regular cow’s milk minus lactose, the natural sugar in milk. It provides all the same healthful nutrients (e.g., protein and calcium), just not the sugar that stokes digestive problems for up to 50 million Americans.

Raw vs. pasteurized? During pasteurization, milk is heated to high temperatures (>161°F) then rapidly cooled to kill harmful bacteria, including salmonella, E.coli 0157:H7 and listeria. While raw-milk enthusiasts claim heating milk destroys its natural enzymes and beneficial bacteria, studies show that the nutritional differences between pasteurized and raw milk are slight. What’s more, public health experts warn that drinking raw milk is like playing Russian roulette. In fact, the Centers for Disease Control and Prevention reported that raw milk accounted for 1,007 illnesses and two deaths between 1998 and 2005. And when USDA scientists collected raw milk samples from 861 farms in 21 states, nearly a quarter of them contained bacteria linked to human illness, including 5 percent that tested positive for Listeria—a bacterium that results in a foodborne illness, listeriosis, and has a 30 percent mortality rate.

Don’t like milk? Don’t have a cow: milk can come from many sources. Though you may drink these plant-based milks in place of what Elsie produces, “Technically, these drinks aren’t really milk,” says Catherine W. Donnelly, Ph.D., of the University of Vermont. Regardless, here’s a milk/“milk” comparison* per cup:

Nutrition notes: One cup provides a third of the recommended daily dose for calcium and 16% of the daily value for protein. It’s a good source of vitamin D (through fortification) and phosphorus, which build strong bones, as well as the B vitamin riboflavin.

Nutrition notes: Like cow’s milk, goat’s milk contains lactose, just a tad less. Many suggest that people who are allergic to cow’s milk can tolerate goat’s milk, but immunologists often advise those allergic to cow’s milk to avoid goat’s milk, too, because of cross-reactivity risks.

Nutrition notes: Studies link soy’s protein and phytoestrogens with a reduced risk of cancer and heart disease. (But when it comes to breast cancer, is soy safe? Find out here.) Choose a soymilk fortified with calcium and vitamin D (30% DV and 25% DV, respectively)—and shake before you pour, as added nutrients can settle to the bottom of the carton.

Brierley's interest in nutrition and food come together in her position as nutrition editor at EatingWell. Brierley holds a master’s degree in Nutrition Communication from the Friedman School of Nutrition Science and Policy at Tufts University. A Registered Dietitian, she completed her undergraduate degree at the University of Vermont.